Adjustment mechanism for axial flow compressors



April 13, 1967 J. c. BURGE ET AL 3,314,595

ADJUSTMENT MECHANISM FOR AXIAL FLOW COMPRESSORS Filed June 9, 1965 2 Sheets-Sheet 1 April 18, 1967 J. c. BURGE ETAL ADJUSTMENT MECHANISM FOR AXIAL FLOW COMPRESSORS 2 Sheets-Sheet 2 Filed June 9, 1965 United States Patent T 3,314,595 ADJUSTMENT MECHANISM FOR AXIAL FLOW COMPRESSORS Joseph C. Burge and Richard. W. Follmer, Cincinnati,

Ohio, assignors to General Electric Company, a corporation of New York Filed June 9, 1965, Ser. No. 462,688 8 Claims. (Cl. 230-114) The present invention relates to improvements in axial flow compressors of the type advantageously used in gas turbine engines and more particularly to improved adjustment mechanism therefor.

Axial flow compressors of the so caller variable geometry or adjustable stator type have been found highly effective for pressurizing air to support combustion in gas turbine engines particularly where such engines are used for the propulsion of aircraft. Compressors of the type referred to comprise a casing and a rotor having stator and rotor blades mounted respectively thereon. The stator and rotor blades are disposed in alternate circumferential rows, with each adjacent pair of rows forming a compressor stage. The blades are disposed generally radially of the rotor with the stator blades of at least the initial stages being pivotal about these radial axes.

By adjusting the pivotally mounted stator blades about such radial axes, it has been found that highly efficient operation of the compressor can be obtained. In making such adjustments it is usually essential that all stators of a given stage be pivoted simultaneously and to the same extent.

The objects of the invention are to provide simple and economical mechanism for adjusting stators in axial flow compressors as well as to provide such adjusting mechanism which fulfills the high performance requirements of axial flow compressors employed in gas turbine engines used for the propulsion of aircraft, these high performance requirements including accuracy, lightness of weight and the ability to respond to control signals generated by computer mechanism which determines the desired angular relationships of the stators.

To these ends, levers are secured to each of the stators of an axial flow compressor of the type above described. Preferably these levers are relatively thin and plate-like and extend in a plane normal to the axes of the stators to which they are attached. An actuator ring is provided for each row of adjustable stators and these levers are pivotally connected thereto. 1

The actuator rings encompass the compressor casing and each comprises a pair of arcuate segments and connectors overlapping the segments and secured thereto to compositely form a ring. The segments and connectors are advantageously tubular in all or certain portions.

This construction of the actuator rings permits the stator levers to either overlie the segments or underlie the connectors at practically any point around the circumference of the ring. The pivotal connections are advantageously made by providing openings in the outer walls of the segments and like openings in the inner walls of the connectors. Tubular inserts project through these openings into circumferential slots in the opposite wall. The stator levers then have pins which project into these tubular inserts, the pins projecting inwardly or outwardly depending on whether they are received by the inserts in the segments or inserts in the connectors. Preferably these inserts are formed of polytetrafluoroethylene impregnated with glass fibers. This gives necessary strength while providing a minimum of friction in the pivotal connection.

Selected, spaced inserts on the segments have thrust buttons secured to their inner ends which engage bearing 3,314,595 Patented Apr. 18, 1967 ICC pads on the compressor casing to more accurately position the actuator rings concentrically of the casing.

A control lever having an I-shaped cross section is pivotally mounted at one end on the compressor casing with its opposite end guided for movement in a flat plane. An actuator, which is responsive to engine control signals, is connected to the movable end of the control lever. Each of the actuator rings is then connected to the control lever by a light weight, adjustable link so that movement of the control lever will be transmitted to the actuator rings and cause the desired simultaneous adjustment of the stators.

The adjustable links each comprise a clevis connected to the control lever, tubular intermediate member rotatable in a hole in the bridge of the clevis and a spherical rod end threaded into the tubular member at one end and connected to the actuator ring at its opposite end.

The intermediate member has a head engaging the bridge of the clevis and a nut threaded onto its outer surface to clamp the clevis bridge against this head and thereby lock the intermediate member relative to the clevis. The intermediate member is also fiatted so that a wrench may be employed to rotate it, when the check nut is loosened to vary the extent to which the rod end is threaded therein and thus adjust the effective length of the link.

The pivotal connection for the clevis comprises a ball journaled in the web of the control lever and a pin extending through the arms of the clevis and the ball. Bosses extend inwardly from the clevis arms to engage the ball and position the clevis laterally of the control lever. The flanges of the control lever are slotted adjacent one end thereof to permit assembly of the clevis thereon without any substantial effect on the strength of the lever itself.

The above and other related objects and features of the invention will be apparent from a reading of the following description of the disclosure found in the accompanying drawings and the novelty thereof pointed out in the appended claims.

In the drawings:

FIG. 1 is an elevation of a gas turbine engine comprising an axial flow compressor having control mecha nism embodying the present invention;

FIG. 2 is an enlarged elevation, with portions broken away and in section, of the axial flow compressor seen in FIG. 1;

FIG. 3 is a section taken on line III-III in FIG. 2;

FIG. 4 is a section, on an enlarged scale taken on line IVIV in FIG. 2;

FIG. 5 is a perspective view of a pivotal connector piece;

FIG. 6 is a section taken on line VIVI in FIG. 2;

FIG. 7 is an exploded view showing means for guiding one end of a control lever seen in FIG. 2; and

FIG. 8 is a view illustrating, in section, the connection of an actuator to this end of the control lever.

FIG. 1 shows a gas turbine engine l of a type in which the present invention may be advantageously incorporated. Air entering the front end of the engine is compressed by an axial flow compressor 12 to provide the proper air pressure for supporting combustion of fuel within a combustor section 14-. The combustion products are discharged through a turbine (not shown) which drives a rotor (identified below) of the axial flow compressor. The energy level of the combustion products may be augmented by the further combustion of fuel in an afterburner 16 and discharged therefrom to provide a propulsive force, as when the engine It is used in the propulsion of an aircraft. Those skilled in the art will recognize that the present invention is directed to improvements pertaining to axial flow compressors and that the gas turbine engine could take other forms.

Reference will be made to the compressor .12 as particularly illustrated in FIGS. 2 and 4. The compressor comprises a plurality of stages with each stage being formed by a circumferential row radially disposed stator blades 17 lying in a given plane and mounted on a cylindrical casing 18, which stator blades cooperate with a circumferential row of rotor blades 19 lying in an adjacent plane and mounted on a rotor 28. In order that the compressor 12 will effectively compress the air for the combustor 14, it is desirable, in accordance with known technology, that the stators of at least the initial stages of the compressor be pivotally adjusted about axes radial of the compressor casing axis during operation of the engine.

To this end each of the adjustable stators has a stub shaft 22 at its outer end which is journaled (FIGS. 2 and by appropriate means in the compressor casing 20. The inner ends of each of the stators 17 is appropriately journaled by means supported from the compressor casing (not shown). It is desired that each of the stators 17 of a given stage be simultaneously pivoted about the axis of the stub shaft 22. Thus for each stage levers 24 having a common effective length are secured to the stub shafts 22. All of the levers 24 for a given stage are connected at their outer ends by means later described in detail to an actuator ring 26 which is mounted for oscillatory movement on the casing 18. Each of the rings 26 is connected by a link 28 to a control lever 38. Preferably two levers 30 are employed on opposite sides of the easing 18 with appropriate connections being made thereto. However, only one lever 30 is shown and the description thereof will apply to the other lever.

The lever 30 is pivotally mounted at one end on a pin 3-2 projecting from a bracket 34 affixed to the compressor casing U8. The opposite end of the lever 30 is connected to the piston rod 36 of an actuator 38 (best seen in FIG. 1). One end of the actuator 38 is pivotally mounted at 40 on the compressor 12. The outer end of the lever 30 to which the rod 36 is attached is guided for reciprocable or oscillating movement in a fixed plane by the means now to be described.

A stud 4-2 (FIGS. 2, 7 and 8) projects from the outer end of the lever 38 and carries a spherical journal member 44 which is part of a rod end 46 secured to the piston rod 36, all of which is assembled on the stud 42 before it is secured to the lever 38. A pair of lugs 48 are formed on the outer end of the stud and are received by slots 50 in a guide piece 52 which is rotated 90 from its disassembled position seen in FIG 7, after being telescoped onto the stud 42. The guide piece 52 is thus locked on the stud 42 when the guide piece is positioned within a channel 54, formed on a bracket 56 which is secured to the compressor casing 18.

The actuator 38 may be controlled by known servo control means, responsive to engine control signals, to position the lever 38 and thereby simultaneously adjust the angular position of all the stators 17 of each of the adjustable stator stages. The extent of pivotal movement imparted to each of the stators of a given stage can be controlled by the preselected length of the lever arms 24 and to some extent adjusted by varying the effective length of the various links 28. A cable 55 secured to the control lever 38 by a further link 28 provides a position feedback function usual in closed loop controls.

It is important that the links 28 be able to freely transmit movement between the lever 30 which is oscillated (by actuator 38) in a plane tangent to the actuator rings 26 whereas the actuator rings oscillate about the axis of the compressor and are displaced axially thereof as the lever arms 24 in turn oscillate about the axes of the stub shafts 22. It is further desirable that the effective lengths of the links 28 be accurately adjustable. Combined with these desired results it is essential for aircraft operation that the overall construction be extremely light weight. These features are provided by the specific construction herein employed which will now be described in detail.

The links 28, each comprise a clevis 58 (FIG. 4), an intermediate member 60 and a rod end 62. The rod end 62 is secured to the actuator ring 26 by a shoulder screw 64 so that universal movement can be had between the link 28 and the actuator ring 26. The upper end of the link 28 is secured to the lever 30 by a pin 66 which passes through a spherical journal member 68, captured in the vertical web of the lever 30. It will be noted that the clevis 58 has inwardly projecting bosses 70 which engage the flatted ends of the spherical journal member 68 to accurately position the clevis 58, relative thereto and thereby provide for universal movement of the link 28 relative to the lever 30.

The intermediate member 60 is provided with a head 72 at its upper end, which bottoms against the bridge of the clevis 58 as the lower portion of the adjusting link extends through an opening therein. The outer surface of the intermediate member 60 is threaded so that a nut 74 may be threaded thereon to clamp the intermediate member relative to the clevis 58. The intermediate member 60 is also interiorly threaded to receive the rod end 62, and a check nut 76 is provided to clamp the rod end relative thereto. The outer surface of the intermediate member 60 is flatted at 78 so that a wrench may be appiled thereto. Tus by slightly loosening the nuts 74 and 76 it is possible to rotate the intermediate member 60 and thereby vary the extent to which the rod end 62 is threaded therein, and in turn adjust the effective length of the link 28.

Referring again to the actuator ring 26, it will be seen that the ring is compositely formed by a pair of arcuate segments 80 having an included angle somewhat less than 180 and joined together at their opposite ends by a connector 82. The segments 80 are advantageously of a square tubular cross section, as best seen in FIG. 4. The connectors 82 are secured thereto by the screws 84 and maintained in spaced relation from the sections 80 by collars 86. Pins 88 serve to accurately position the connectors 82 relative to the segments 80.

In some instances the stators 17 of a given stage may be very closely spaced in an angular sense, one from another, and the levers 24 secured thereto will therefore extend not only to the segments but to the connector 82 and also between the segment 80 and connector 82 as can be seen in FIGS. 2 and 4.

The pivotal connection between the levers 24 (FIGS 4-6) and the actuator ring 26 uniquely accommodates any one of these situations. Thus it will be seen that the levers 24 are relatively thin, flat, and therefore can be reversible. A pin 90 is secured to the outer end of each lever 24 and is disposed radially of the compressor casing 18 when the lever 24 is aligned with the casing axis, as illustrated in FIG. 4. The pin 90 is telescoped into a bushing 92 which is secured in the ring 26. The bushing 92 is preferably formed of polytetrafluoroethylene impregnated with glass fibers and has a head 94 on one end which limits the extent to which it may be telescoped through holes 96 in the outer surfaces of the segments 80 and inner surfaces of the connectors 82. The outer end of the sleeve 92 (FIG. 5 is fiatted and passes through slots formed either on the inner surfaces of the segments 80 or the outer surface of the connectors 82. Beads are formed on the flatted outer end portions of the inserts 92 to provide detent means for releasably holding the inserts on either the segments 80 or connectors 82.

It will be appreciated that as the levers 24 swing in a flat plane, the rings 26 oscillate about the axis of the casing 18 and also move axially relative thereto. Further it will be appreciated that the outer ends of the inserts swing back and forth in the slots 98 as the pins 90 pivot relative to the ring 26 due to the compound movements involved. Because the levers 24 are constrained for movement in a flat plane, the ends will either be flexed or the pins 90 will ride slightly out of the inserts 92 or the inserts may shift slightly relative to the actuator rings 26. Any one of these possibilities may occur, but none will affect the accuracy of the adjustment which is to be obtained.

The levers 24 connected to the segments 80 are preferably preflexed outwardly a slight amount and the levers 24 connected to the connectors 82 are flexed inwardly a slight amount so that the actuator ring in fact is positioned thereby on the compressor. By prefiexing the levers, the tendency for any relative movement between the lever ends and the actuator ring due to the flat plane in which the levers are constrained to follow is thereby minimized.

In order to further insure accuracy in the positioning of the actuator ring 26 on the casing 18, thrust buttons 102 are secured to the outer ends of selected inserts 92 and held thereon by cotter pins 1%. The thrust buttons 1&2 engage bearing pads 106 formed on the casing 18.

In order to assemble the links 28 and the clevis members 58 on the lever 30, inwardly projecting bosses '70 of the clevis 53 can be slid through slots 108 and 110 formed in the bottom reinforcing rib of the lever 30. These slots are provided at both ends of the lever for ease of assembly. This can best be seen in FIGS. 2 and 3.

From the above description it will be apparent that the present control system for adjusting the angular disposition of the stators is highly effective in providing a high degree of accuracy with a minimum of weight in a very economical manner.

Various modifications of the specific structural elements herein disclosed will be apparent to those skilled in the art Within the scope of the present inventive concepts which are to be derived solely from the following claims.

Having thus described the invention, what is claimed as novel and desired to be secured by Letters Patent of the United States is:

1. For use in combination with an axial flow compressor of the type having a casing, a rotor therein and alternate circumferential rows of stator and rotor blades mounted respectively on the casing and rotor to form a plurality of compressor stages, the stator blades of at least the initial stages being pivotal about axes radial of the rotor axis,

stator adjustment mechanism comprising a relatively thin lever secured to each stator and extending in a plane normal to the plane of that stator,

an actuator ring for each row of stators,

each actuator ring comprising a pair of arcuate seg ments of square tubular cross section and connectors, in part tubular, overlapping the segments, spaced outwardly therefrom and secured thereto to compositely form a ring,

at least a portion of the levers of each row extending into overlying relation with the ring segments for that row and in at least one row a portion of the levers extending between the segments and connectors and another portion extending into underlying relation with the connectors,

each of the levers having a pin projecting from the plane thereof,

said segments having openings in the outer walls thereof and aligned circumferential slots in their inner walls,

said connectors having holes in their inner walls and aligned circumferential slots in their outer walls, inserts formed of polytetrafluoroethylene impregnated with glass fibers, said inserts being generally tubular in form and having a head at one end and being flatted at their opposite end with beads adjacent the terminus of the opposite end, said inserts being compressor 6 telescoped through the holes in said segments and connectors with their flattend ends being received by said slots and with the inserts retained on said segments and connectors by the heads and beads thereon,

the pins on said levers being pivotal-ly received by the inserts to synchronize movement of all of the stators of each stage,

selected and arcuately spaced inserts projecting through said segments, having thrust buttons telescoped over their lowed ends,

said compressor casing having formed thereon bearing pads engaged by said thrust buttons to accurately :position the actuating rings relative to said compressor casing,

a control lever of I-shaped cross section pivotally mounted at one end on the compressor casing and guided at its opposite end for movement in a flat plane,

an actuator pivotally connected to said opposite end of the control lever for oscillating the control lever,

adjustable links connecting the control lever and the actuator rings,

each adjustable link comprising a clevis connected to the control lever,

a tubular intermediate member rotatable in a hole in the bridge of said clevis and having a head resting on the bridge,

said intermediate member being threaded on its outer and inner surfaces, and

a rod end threaded into said tubular member at one end and connected to the actuating ring at its opposite end,

a check nut threaded onto the outer surface of said intermediate member to clamp the intermediate member relative to the clevis,

the lower end of said intermediate member being flatted so that a wrench may be applied thereto and with the check nut loosened, the intermediate member rotated to adjust the extent to which the rod end is threaded therein, thereby adjusting the effective length of the link,

the connection of each adjustable link to the control lever comprising a ball journaled in the vertical Web of the control lever and a pin passing through the arms of the clevis and the ball,

said clevis having inwardly extending bosses to position the adjusting link relative to the ball,

the flange of said control lever being notched on opposite sides of its web and adjacent one end thereof to facilitate assembly of the clevises thereon.

2. For use in combination with an axial flow compressor of the type having a casing, a rotor therein and alternate circumferential rows of stator and rotor blades mounted respectively on the casing and rotor to form a plurality of compressor stages, the stator blades of at least the initial stages being pivotal about axes radial of the rotor axis,

stator adjustment mechanism comprising a relatively thin lever secured to each stator and extending in a plane normal to the plane of that stator,

an actuator ring for each row of stators,

each actuator ring comprising a pair of arcuate segments of square tubular cross section and connectors, in part tubular, overlapping the segments, spaced outwardly therefrom and secured thereto to compositely form a ring,

at least a portion of the levers of each row extending into overlying relation with the ring segments for that row and in at least one row a portion of the levers extending between the segments and connectors and another portion extending into underlying relation with the connectors,

each of the levers having a pin projecting from the plane thereof said segments having openings in the outer Walls thereof and aligned circumferential slots in their inner walls, said connectors having holes in their inner walls and aligned circumferential slots in their outer walls, inserts formed of polytetrafluoroethylene impregnated with glass fibers, said inserts being generally tubular in form and having a head at one end and being flatted at their opposite end with with beads adjacent the terminus of the opposite end, said inserts being telescoped through the holes in said segments and connectors with their flatted ends being received by said slots and with the inserts retained on said segments and connectors by the heads and beads thereon, the pins on said levers being pivotally received by the inserts to synchronize movement of all of the stators of each stage, selected and arcuately spaced inserts projecting through said segments, having thrust buttons telescoped over their lower ends, said compressor casing having formed thereon bearing pads engaged by said thrust buttons to accurately position the actuating rings relative to said compressor casing, and means for simultaneously oscillating said actuator rings to thereby adjust the stators in accordance with the operating conditions of the compressor. 3. For use in combination with an axial flow compressor of the type having a casing, a rotor therein and alternate circumferential rows of stator and rotor blades mounted respectively on the casing and rotor to form a plurality of compressor stages, the stator blades of at least the initial stages being pivotal about axes radial of the rotor axis,

stator adjustment mechanism comprising a lever secured to each stator and extending in a plane normal to the plane of that stator, an actuator of tubular form ring for each row of stators, at least a portion of the levers of each row extending into overlying relation with the ring, each of the levers having a pin projecting from the plane thereof, said rings having openings in the outer falls thereof and aligned circumferential slots in their inner walls, inserts formed of polytetrafluoroethylene impregnated with glass fibers, said inserts being generally tubular in form and having a head at one end and being fiatted at their opposite end, said inserts being telescoped through the openings in said rings with their fiatted ends being received by said slots, the pins on said levers being pivotally received by the respective inserts to synchronize movement of all of the stators of each stage, and means for simultaneously oscillating said actuator rings to thereby adjust the stators in accordance with the operating conditions of the compressor. 4. For use in combination with an axial flow compressor of the type having a casing, a rotor therein and alternate circumferential rows of stator and rotor blades mounted respectively on the casing and rotor to form a plurality of compressor stages, the stator blades of at least the initial stages being pivotal about axes radial of the rotor axis,

stator adjustment mechanism comprising a relatively thin lever secured to each stator and extending in a plane normal to the plane of that stator, an actuator ring for each row of stators,

means pivotally connecting the lever arms of each row to the actuator ring associated therewith,

a control lever of I-shaped cross section pivotally mounted at one end on the compressor casing and guided at its opposite end for movement in a fiat plane,

an actuator pivotally connected to said opposite end of the control lever for oscillating the control lever,

adjustable links connecting the control lever and the actuator rings,

each adjustable link comprising a clevis connected to the control lever,

a tubular intermediate member rotatable in a hole in the bridge of said clevis and having a head resting on the bridge,

said intermediate member being threaded on its outer and inner surfaces, and

a rod end threaded into said tubular member at one end and connected to the actuating ring at its opposite end,

a check nut threaded onto the outer surface of said intermediate member to clamp the intermediate member relative to the clevis,

the lower end of said intermediate member being flatted so that a Wrench may be applied thereto and with the check nut loosened, the intermediate member rotated to adjust the extent to which the rod end is threaded therein, thereby adjusting the effective length of the link,

the connection of each adjustable link to the control lever comprising a ball journaled in the vertical web of the control lever and a pin passing through the arms of the clevis and the ball,

said clevis having inwardly extending bosses to position the adjusting link relative to the ball,

the flange of said control lever being notched on opposite sides of its web and adjacent one end thereof to facilitate assembly of the clevises thereon.

5. For use in combination with an axial flow compressor of the type having a casing, a rotor therein and alternate circumferential rows of stator and rotor blades mounted respectively on the casing and rotor to form a plurality of compressor stages, the stator blades of at least the initial stages being pivotal about axes radial of the rotor axis,

stator adjustment mechanism comprising a relatively thin lever secured to each stator and extending in a plane normal to the plane of that stator,

an actuator ring for each row of stators,

means pivotally connecting the lever arms of each row to the actuator ring associated therewith,

a control lever of I-shaped cross section pivotally mounted at one end on the compressor casing and guided at its opposite end for movement in fiat plane,

an actuator pivotally connected to said opposite end of the control lever for oscillating the control lever, 1

adjustable links connecting the control lever and the actuator rings,

each adjustable link comprising a clevis connected to the control lever,

a tubular intermediate member rotatable in a hole in the bridge of said clevis and having a head resting on the bridge,

said intermediate member being threaded on its outer and inner surfaces, and

a rod end threaded into said tubular member at one end and connected to the actuating ring at it pposi e end,

a check nut threaded onto the outer surface of said intermediate member to clamp the intermediate member relative to the clevis,

the lower end of said intermediate member being flatted so that a wrench may be applied thereto and with the check nut loosened, the intermediate member rotated to adjust the extent to which the rod end is threaded therein, thereby adjusting the eifective length of the link.

6. For use in combination with an axial flow compressor of the type having a casing, a rotor therein and alternate circumferential rows of stator and rotor blades mounted respectively on the casing and rotor to form a plurality of compressor stages, the stator blades of at least the initial stages being pivotal about axes radial of the rotor axis,

stator adjustment mechanism comprising a plurality of actuating rings circumferentially surrounding the compressor casing, each actuating ring being offset axially from a respecive row of pivoted stator blades,

a plurality of relatively thin levers each secured to a respective stator blade outwardly of the compressor casing and extending axially therefrom to the respective actuating ring in a plane substantially normal to the axis of the stator blade,

means pivotally connecting each of said levers to the respective actuating ring about an axis substantially radial of the rotor axis, said connecting means further permitting limited relative movement between the interconnected lever and actuating ring along the pivotal axis,

an elongated control lever extending across said actuating rings in a generally axial direction relative to the rotor axis,

means at one end of said control lever pivotally mounting said control lever to the compressor casing for movement in a flat plane, and actuating means connected to said control lever for oscillating said control lever within said plane,

a plurality of axially spaced-apart links each extending between said control lever and a respective one of said actuating rings and having connecting means of the universal type at opposite ends thereof for connecting the link to said control lever and the respective actuating ring,

whereby movement of said control lever by said actuating means causes simultaneous and corresponding movement of said actuating rings and the associated stator blades,

and means for adjusting the lengths of said links such that the corresponding movement between said control lever and said actuating rings and the associated stator blades can be varied.

7. Stator adjusting mechanism as defined by claim 6 in which the means for pivotally connecting each of said levers to the respective actuating means comprises:

a pin secured to the respective lever and projecting perpendicularly therefrom,

and a tubular insert carried by the respective actuating ring for receiving said pin along said axis radial of the rotor axis,

whereby said pin may pivot Within said tubular insert and move along said axis.

8. Stator adjusting mechanism as defined by claim 7 in which said insert is formed of polytetratluoroethylene impregnated with glass fibers.

References Cited by the Examiner UNITED STATES PATENTS 2,371,706 3/1945 Planiol 253-78 2,842,305 7/1958 Eckenfels et a1 230-114 2,933,235 4/1960 Neumann 230-ll4 3,056,541 10/1962 Foweraker 230-114 DONLEY J. STOCKING, Primary Exmminer. SAMUEL FEINBERG, Examiner. HENRY F. RADUAZO, Assistant Examiner. 

1. FOR USE IN COMBINATION WITH AN AXIAL FLOW COMPRESSOR OF THE TYPE HAVING A CASING, A ROTOR THEREIN AND ALTERNATE CIRCUMFERENTIAL ROWS OF STATOR AND ROTOR BLADES MOUNTED RESPECTIVELY ON THE CASING AND ROTOR TO FORM A PLURALITY OF COMPRESSOR STAGES, THE STATOR BLADES OF AT LEAST THE INITIAL STAGES BEING PIVOTAL ABOUT AXES RADIAL OF THE ROTOR AXIS, STATOR ADJUSTMENT MECHANISM COMPRISING A RELATIVELY THIN LEVER SECURED TO EACH STATOR AND EXTENDING IN A PLANE NORMAL TO THE PLANE OF THAT STATOR, AN ACTUATOR RING FOR EACH ROW OF STATORS, EACH ACTUATOR RING COMPRISING A PAIR OF ARCUATE SEGMENTS OF SQUARE TUBULAR CROSS SECTION AND CONNECTORS, IN PART TUBULAR, OVERLAPPING THE SEGMENTS, SPACED OUTWARDLY THEREFROM AND SECURED THERETO TO COMPOSITELY FORM A RING, AT LEAST A PORTION OF THE LEVERS OF EACH ROW EXTENDING INTO OVERLYING RELATION WITH THE RING SEGMENTS FOR THAT ROW AND IN AT LEAST ONE ROW A PORTION OF THE LEVERS EXTENDING BETWEEN THE SEGMENTS AND CONNECTORS AND ANOTHER PORTION EXTENDING INTO UNDERLYING RELATION WITH THE CONNECTORS, EACH OF THE LEVERS HAVING A PIN PROJECTING FROM THE PLANE THEREOF, SAID SEGMENTS HAVING OPENINGS IN THE OUTER WALLS THEREOF AND ALIGNED CIRCUMFERENTIAL SLOTS IN THEIR INNER WALLS, SAID CONNECTORS HAVING HOLES IN THEIR INNER WALLS AND ALIGNED CIRCUMFERENTIAL SLOTS IN THEIR OUTER WALLS, INSERTS FORMED OF POLYTETRAFLUOROETHYLENE IMPREGNATED WITH GLASS FIBERS, SAID INSERTS BEING GENERALLY TUBULAR IN FORM AND HAVING A HEAD AT ONE END AND BEING FLATTED AT THEIR OPPOSITE END WITH BEADS ADJACENT THE TERMINUS OF THE OPPOSITE END, SAID INSERTS BEING TELESCOPED THROUGH THE HOLES IN SAID SEGMENTS AND CONNECTORS WITH THEIR FLATTENED ENDS BEING RECEIVED BY SAID SLOTS AND WITH THE INSERTS RETAINED ON SAID SEGMENTS AND CONNECTORS BY THE HEADS AND BEADS THEREON, THE PINS ON SAID LEVERS BEING PIVOTALLY RECEIVED BY THE INSERTS TO SYNCHRONIZE MOVEMENT OF ALL OF THE STATORS OF EACH STAGE, SELECTED AND ARCUATELY SPACED INSERTS PROJECTING THROUGH SAID SEGMENTS, HAVING THRUST BUTTONS TELESCOPED OVER THEIR LOWED ENDS, SAID COMPRESSOR CASING HAVING FORMED THEREON BEARING PADS ENGAGED BY SAID THRUST BUTTONS TO ACCURATELY POSITION THE ACTUATING RINGS RELATIVE TO SAID COMPRESSOR CASING, A CONTROL LEVER OF I-SHAPED CROSS SECTION PIVOTALLY MOUNTED AT ONE END ON THE COMPRESSOR CASING AND GUIDED AT ITS OPPOSITE END FOR MOVEMENT IN A FLAT PLANE, AN ACTUATOR PIVOTALLY CONNECTED TO SAID OPPOSITE END OF THE CONTROL LEVER FOR OSCILLATING THE CONTROL LEVER, ADJUSTABLE LINKS CONNECTING THE CONTROL LEVER AND THE ACTUATOR RINGS, EACH ADJUSTABLE LINK COMPRISING A CLEVIS CONNECTED TO THE CONTROL LEVER, A TUBULAR INTERMEDIATE MEMBER ROTATABLE IN A HOLE IN THE BRIDGE OF SAID CLEVIS AND HAVING A HEAD RESTING ON THE BRIDGE, SAID INTERMEDIATE MEMBER BEING THREADED ON ITS OUTER AND INNER SURFACES, AND A ROD END THREADED INTO SAID TUBULAR MEMBER AT ONE END AND CONNECTED TO THE ACTUATING RING AT ITS OPPOSITE END, A CHECK NUT THREADED ONTO THE OUTER SURFACE OF SAID INTERMEDIATE MEMBER TO CLAMP THE INTERMEDIATE MEMBER RELATIVE TO THE CLEVIS, THE LOWER END OF SAID INTERMEDIATE MEMBER BEING FLATTED SO THAT A WRENCH MAY BE APPLIED THERETO AND WITH THE CHECK NUT LOOSENED, THE INTERMEDIATE MEMBER ROTATED TO ADJUST THE EXTENT TO WHICH THE ROD END IS THREADED THEREIN, THEREBY ADJUSTING THE EFFECTIVE LENGTH OF THE LINK, THE CONNECTION OF EACH ADJUSTABLE LINK TO THE CONTROL LEVER COMPRISING A BALL JOURNALED IN THE VERTICAL WEB OF THE CON TROL LEVER AND A PIN PASSING THROUGH THE ARMS OF THE CLEVIS AND THE BALL, SAID CLEVIS HAVING INWARDLY EXTENDING BOSSES TO POSITION THE ADJUSTING LINK RELATIVE TO THE BALL, THE FLANGE OF SAID CONTROL LEVER BEING NOTCHED ON OPPOSITE SIDES OF ITS WEB AND ADJACENT ONE END THEREOF TO FACILITATE ASSEMBLY OF THE CLEVISES THEREON. 